The removal of oxidisable stains from either hard surfaces or fabrics by means of peroxygen bleaches at temperatures less than about 60.degree. C. is a well known technique and customarily involves the use of organic peroxy acids. The most commonly used peroxy acid is peracetic acid, normally generated in situ in the bleaching or laundry liquor by the reaction of alkaline hydrogen peroxide with a peroxy acid precursor (the so-called bleach activator). However, peroxyacids containing more than 2 carbon atoms in the acyl group have also been disclosed and taught for this purpose and GB-A-864,798, CA-A-635,620, U.S. Pat. No. 4,100,095, U.S. Pat. No. 4,119,960, U.S Pat. No. 4,126,573, EP-A-0,068,547 and EP A-0,120,591 all relate to the formation, stabilisation or use of such materials.
Recently, as described in EP-A-0,068,547 and EP-A-0,120,591 it has been found that selection of the chainlength of the aliphatic moiety of the peroxy acid permits the peroxy acid to be concentrated in the area where stain removal is required. Thus, whereas for removal of fugitive dyestuffs in bulk solution, a `hydrophilic` bleach species is satisfactory, for stains on solid surfaces a bleaching species showing more hydrophobic character, and hence a tendency to migrate to the solid-liquid interface, may be more beneficial. In EP-A-0,068,547 and EP-A-0,120,591, bleach activator compositions which generate these so-called "hydrophobic" bleaching species are described in detail.
It has now been found that under certain usage conditions, bleaches and bleach activators of the "hydrophobic" class can have an adverse effect on certain varieties of water-insoluble polymer-based substrates, typically those containing unsaturated moieties or having a high degree of polymer cross-linking. Although the reasons for this are not fully understood, the effect appears to be associated with a side-reaction to the main bleaching process involving a single-electron, free radical mechanism.
The present invention therefore provides bleaching and detergent compositions incorporating a hydrophobic bleach activator component and which is safe and effective to use over the full range of usage conditions and substrate types, inclusive of those containing unsaturated or cross-linked polymeric moieties.